5Pcs LM393 Speed Sensor Detection Speed Module For ArduinoFeatures:Working voltage: 3.3V~5VWeight: 8gDimensions: Approx.3.2 x 1.4 x 0.7cm5mm Groove widthUsing wide voltage LM393 comparatorApplication: Widely used in dynamo speed detecting、 pulse counting、 etcOutput form: Digital switch output (0 and 1) and Analog for Sensitivity.Package included:5 x Speed sensor